Answer
H.R. McMaster served as a captain in the 2nd Cavalry Regiment during the Battle of 73 Easting. The battle took place on February 26, 1991, during the Gulf War. McMaster was the commander of a troop of M1A1 Abrams tanks. He was responsible for leading his troop in an attack on Iraqi forces that were dug in on the east bank of the Euphrates River.